This project will study the membrane properties of glycosphingolipids. The carbon-13 nuclear magnetic resonance spectra of such molecules when they are incorporated into phospholipid bilayer vesicles will be determined, and the spin-lattice relaxation times will be interpreted in terms of the conformational mobilities of these molecules within the membrane and in terms of their effect on the membrane organization. Photoactivable derivatives of glycosphingolipids and other membrane components will be used to investigate cross-linking of neighboring molecules within membrane structures, giving concrete, covalent evidence of the proximity of such molecules. The photochemical reaction products within membrane structures will be identified and used as evidence of the molecular arrangements within membranes. Glycosphingolipids are important membrane components, and one class, gangliosides, is particularly important in neural tissue. Therefore, it is believed that the work to be done will contribute to the understanding of important biochemical questions about membrane structure and function. Because gangliosides may be involved in neurotransmission and cell surface recognition processes, it is also believed that these basic studies could give information relevant to medically important areas such as mental disease and cancer.